Drive for photographic material



March 25, 1952 E. H. HEYER 2,590,699

DRIVE FOR PHOTOGRAPHIC MATERIAL Filed 00%. 20, 1947 3 Sheets-Sheet 1 W AA/4 March 25, 1952 EH. H EYER DRIVE FOR PHOTOGRAPHIC MATERIAL 3 Sheets-Sheet 2 Filed Oct. 20, 1947 II. I||l INVENTOR.

5. H. HEYER DRIVE FOR PHCTOGRAPHIC MATERIAL March 25, 1952 Filed 001:.

5 Sheets-Sheet 3 INVENTOR. I

Patented Mar. 25, 1952 7 UNITED STATES PATENT OFFICE DRIVE FOR PHQTOGRAPHIC MATERIAL Eric H. Heyer, Los Angeles, Calif. Application October 20, 1947, Serial No. 780,914

8 Claims. (Cl. 271-23) This invention relates to film developing apparatus, and particularly to a driving systemfor advancing film strips through the series of solutions and fluids required to develop, fix, wash, and dry the film.

The continuous developing of motion picture film through a series of developing, fixing, and washing tanks and drying cabinets is well-known. It is also well-known that raw film stock, when immersed in thedifierent solutions, expands or stretches, whileitcontracts or shrinks during the drying process. These facts necessitate a film advancing medium which compensates for, these variations in length during the developing and drying treatment of the film, while providing proper and equalized tension throughout the film length. Injcolor photography,. where the number of process steps is many times that for black and white film, the film drive is particularly important to obtain the correct timing of each step.

This problem has been solved by others in various ways, an on and off frictional drive being disclosed in United States Patent No. 2,146,170 of February '7, 1939. The majority of prior developing machines are adapted to motion picture film having sprocket holes for metering the film, the constant width of the film permitting standard guide and drive rollers to be used." The present invention is suitable for any width film material with or without'sprocket holes, such as roll films, amateur prints and paper, etc., and provides substantially equal tension in all] film loops,,regardless of changes in length, while automatically guiding the film strip, regardless of its width. The invention makes possible the continuous development of emulsions on paper strips which have very low tensile strength. The simultaneous developing of two or more film strips side by side is also possible, a film end safetygrip being provided together with a safety release feed. The principal object of the invention, therefore, is to facilitate the developing of photosensitive emulsions in strip form.

, Another object of the invention is to provide an improved feed or advancing mechanism for photographic film or print stock.

A further object of the invention is to provide an improved film strip drive in which substantially uniform tension is obtained along the length of the film throughout the developing process.

A still further object of the invention is to provide' a metering drive with safety feed release and film end grip.

A still further object of the invention is to provide an automatic film roller guide for film or print strips without edge contact of the strips withaguiding means.

Although the novel features which are believed to be characteristic of this invention will be pointed out with particularity in the appended 2' mode of its operation will be better understood by referring to' .the following description read in conjunction with the accompanying drawings, forming a partliereof, in which:

Fig. l is a plan view of the general arrangement of the film drive embodying the invention.

Fig. 2 is an elevational view of the film drive shown in Fig. 1].

Fig. 3 is an enlarged, elevational view of the metering and safety release features used in the film drive of the invention. 1

Fig. 4 is a cross-sectional view of one of the drive rollers of the invention taken along the line 4-4 of Fig. 3. 1 1

Fig. 5 is a perspective view of a multiplestrip drive roller usable in the invention.

Fig.6 is a cross-sectional view of a modification of a drive roller of the invention.

Fig. 7 is a, combination diagrammatic and perspective view of an automatic guide roller for the filmstrips, and

Fig. 8 is a partial view of a modification of the control portion of the guide roller system of Fig. 7.

Referring now to the drawings, in which the same numerals identify like elements, an accumulator cabinet 5 receives a film strip 6 from a roll 1, after, passing through a switch 9 normally held open by the film, a roller l0, through thejaws |2 ofa solenoid l3, and over a roller IS. The film then passes around weighted roller It} and over roller H to the metering and safety release rollers ;Zjl and 2|. In Fig. 1, theme'tering roller 2| is shown driven from a motor 23 through a variable speed reducer box 24, and then through any suitable positivedrive 25 such as shafts and gears, chains and sprockets, or belts and pulleys.

The speed of roller 2| is adjustable by box 24 to permit any desired amount of film or print stock to be fed to the developing tank 28 over roller 2] in any given period of time depending upon the type of emulsion being processed, the type of declaims, the manner of its organization and the veloper being used, and the temperature of the developer. Since the roller 20 provides a tight wrap over roller 2| which is solidly fastened to its drive shaft, by the tension of a spring 29 con nected to roller arm 30 and anchor support 3|, accurate metering of the film fed to the developer is obtained. p

The arrangement of rollers 2|] and 2| also provides asafety release for the film drive in the event of a loop loss' in the accumulator. This is accomplished by having the arm 30 rotatable on the axis of roller 2| and the tension of spring 29 such that before the tensile strength of the film strip is exceeded, the arm 30 is rotated against the spring tension to a stop position shown by the dotted lines (see Fig. 3) where the roller-'20 isagain held in release position by the spring '29 against a stop 32. Now, since the surface of roller 2| is belowthe straight line path between the surfaces of rollers l1 and 21, which the film strip When the end of the film passes switch 9, permitting it to close, energy is supplied to solenoid l3 from any suitable source of supply such as a battery 33, which closes jaws Hand holds. the

end of the film stationary. This operation may also energize a signal so .that an operator may be apprised of the fact that the end of the filmroll is' reached, an'd'he can attach the end ofnew'film' roll thereto or a; leader, the 4' time-for this op- "eration' being provided b the: film loop' in the 48 by an idler rollerv 5B tensioned byaspringi52 similarly to the arrangement of roller 20 -2 I, the

rollers 48-50 compensating for momentary increases in film tension due to drybox contraction.

It is to be understoodjthat other developing stepsv ..may. be used with the same strip drive,-.since the film expands and contracts in length as} it passes through the liquids and dryv air, the rollers 35 and. 31- 52 being 'dr iven. in a novel manner. First, a positive drive is provided betweenspeed .control box 24 and a second speed control box 5|,

which provides a predetermined constant speed for the shafts 53 of the above-mentioned rollers. The rollersat the bottom of thetank such as 55 and 58 are idler rollers and not driven inany manner, they, being supported on rods 51, as shown in Fig. 4.

The shafts 53 of each of the top rollers are driven through belts, chains, or shafts as shown diagrammatically at58, while the roller 48 may have a clutch release Edto stop the film during the exchange of take-up reels- The clutch Bil also provides for more positive'drivefor. the roller 58, theroller 50 providing the necessary safety factor in view of the-more positive drive. In

Fig. 4, the roller 31 is shown as a cylinder 5!,

preferably slightly crowned (see Fig. 6), and having end. bearing discs 52 and 53. These discs are of any, oil-less bearing material such as Parock, which is a rubber graphite composition containing approximatelyeighty percent graphite. Another suitable material is Grafit'ar," a carbon and graphite composition. These materials-,- are not affected by developing solutions, re-

driven at substantially twice the-rotational speed required. to pass the film through. the tanks. This shaft speed iscontrolled by controlbox-5I in relation to the speed of metering roller 2!. The shafts 53, ofcourse; rotate on standard bearings 64 and in which each isrnounted. If too 'speed canaccommodatei- The frictionallpullibe tweemtheshaits n ands-the: bearing: materiahof the discs 62 is substantially a constant at any certain shaft speed, the discs having bearing surfacesof. a predetermined .area to maintain this constant frictional drive. For instance, since each drive roller takes care of the frictional loss in the idler roller, such as 55 or 56, just ahead of it, there is no accumulation or building up of tension in'the film strip at an point in the film path through the developin process. Where contraction occurs, the drive shafts handling this portionof the-filmstrip may be rotated slower than the other shafts handling the expanding.

portions of the strip to compensate-for shrinkage and contraction of the film. This is accomplished by varying-the pulley-or gear sizesof the respective drive shafts Referring to Fig. 2, a jet or high velocity spray nozzle 61 is illustrated, this nozzle addingturbu lence to the developer to provide better chemical actionbetween the developer and emulsions. However, these devices increase the solution drag on the-film, and tend to increase the-film loop; and a greater drivingtension or force is, therefore, required than that provided simply by the friction between shafts 53 and discs=6-2--63; which is sufiicient for normally agitated solutions and to overcome the friction of the'lower idler rollers such as 55 and 56. To add the-desired amount of frictional drive where spray nozzles are used, the end clutch shownin'Fig. 6 is used,.wherein a non-corrosive metal or" plastic disc 69 is pressed against a graphite bushin -or disc 16, similarly to discs 62-53 of Fig; 4, bya spring 12 having one end abutting a flange 13 threadedly adjustable on the shaft 53. The flange 13 may not necessarily be threaded; but may be siidable on shaft 53 to the desired-position and locked with a set screw to the shaft. By this arrangement, however, certain rollers. such as 35, 40, and 42' may be more strongly'driven than the other rollers to provide the proper ad vancement of the film strip. In Fig. 6, it is noted that the surface of roller (Sis Slightly, crowned, and by utilizingthis prin ciple, a film strip will remain centralized on the roller. Rollers with two or more crowns, as shown at T! and 18 on roller "19 in Fig. 5 may ad'- vance a plurality of film strips simultaneously through the developing machine whilemaintaining eachfilm orv paper strip in its respective path. To obtain more positive strip, uiding which may. be necessary where wet film strips of paperbases are driven over smooth rollers, the devices of Figs. '7 and 8. have beenprovided.

Referring now to Figs. '7 and, 8, an idler roller 8| which may. be cylindrical if desired, or slightly crowned, has safetyfiangesBZ at the. ends .thereof.- This roller may also be a drive roller-[by connecting a flexible shaft thereto. The. roller 8| is sufficiently long to accommodate the widest film or paper strip to be developed. Thisroller ismounted on a yoke 84 pivoted at 85 andhaving its end 86 attached to a nut 88 threaded on a screw shaft 89. The shaft'89 has one end mounted I for rotation in a. bearing 9! andthe other end attached to the shaft'of a reversible motoru82'. On each side of a film strip 93 are adjustable micro switches and- 96 having theirrollers' 91 and 98 positioned slightly away from the: edge ofithe strip 93 when the strip is properly centered on the roller 8|. The switches 95' and 96' are adjustable to accommodate the width of. the filmstrip. being processed. Now, shouldv thezstrip 93 move to oneilside. or. the, other on. the; roller, due; such: reasons: as; unequal .contractiomiz. or

5 expansions of the film, one of the switches 95 or 96 will be closed, which will energize the motor 92 from a suitable power source I to tilt the axis of the roller 8| in a direction to cause the film to return to its centralized position. The three conductor energizing system for the motor will drive the nut 88 in the proper direction in accordance with whichever energizing switch is closed by the strip 93.

As mentioned above, this developing apparatus drive is also suitable for paper photographic stock which, when wet, has little stiffness, rigidity, or tensile strength compared with film having a nitrate and acetate base. To permit such paper strips to be guided on rollers 8 I, the photoelectric cell control arrangement shown in Fig. 8 has been provided. The strip 93 now has its edges adjacent and between two light beams I and I06 projected by lamps I01 and I08, respectively, toward photocells I09 and H0. To protect the undeveloped or partially developed emulsion, the lamps I01 and I08 may be infrared or enclosed visible light lamps with filters I I3 and I I4 with a cut-01f frequency beyond the sensitiveness of the emulsion being developed. Now, when the strip 93 moves ofi position intercepting one or the other of beams I05 or IE0, the resulting electrical pulse is amplified in respective amplifier H6 or II! which is transmitted to the control circuit of motor 92 to drive it in a direction to return the strip to its proper position on roller 8|. By equipping several of the series of driving rollers 21, 35, and 31 to 42 or idler rollers I5 or H with guiding mechanisms, as shown in Figs. 7 and 8, perfect guiding of various width film or paper stock may be safely obtained, while being advanced through the necessary series of developing tanks and cabinets for any type of emulsion. As mentioned above, the drive rollers would be driven with flexible shafts.

I claim:

1. A drive mechanism for a developing machine to advance photographic material comprising a support, a plurality of driving rollers on said support, a plurality of intermediate idler rollers on said support, a roller for determining the rate of feed of a film into said machine, a roller swingable about the axis of said feed roller, said photographic material passing around said swingable roller and then reversely around said feed roller, resilient means associated with said swingable roller for exerting a predetermined tension in said photographic material as said material passes around said swingable roller, a greater tension than said predetermined tension in said material swinging said swingable roller about said feed roller to a position to disengage said photographic material from said feed roller,

,and means for driving said driving rollers to maintain a substantially uniform tension in .said film between said rollers.

2. A photographic stock developing machine drive comprising a roll of photographic stock, a loop switch positioned adjacent said roll and adapted to close when the end of said roll passes said switch, a stock grip controlled by said switch, a positively driven feed roller for determining the speed of advancement of said stock into said machine, said stock being wrapped around a substantial portion of the surface of said feed roller, means for decreasing the amount of wrap of said stock around said feed roller to release said stock from said feed roller when said stock grip is actuated, and a plurality of drive rollers for said stock, said drive rollers being frictionally overdriven.

3. A photographic stock developing machine in accordance with claim 2, in which means are provided for guiding said stock over said drive rollers, said means including a mount for'said rollers, means for tilting said mount to tilt the axis of said rollers, and means actuated by the stock for controlling the tilting of said mount.

4. A photographic stock developing machine in accordance with claim 3, in which said last mentioned means include switches actuated by the movement of said stock from a predetermined position on said rollers.

5. A drive for photographic strip material comprising a frame, a strip supply reel, a positively driven metering roller for taking said strip from said reel and feeding said strip at a uniform rate, a plurality of rollers for advancing said strip after leaving said metering roller, means for frictionally driving certain of said plurality of rollers at different speeds to maintain substantially uniform tension in said strip, and a spring tensioned roller for Wrapping said strip around a substantial portion of said metering roller, a predetermined overtension in said strip reducing "the amount of wrap of said strip around said roller to release said strip from said spring tensioned and metering rollers.

6. A drive in accordance with claim 5, in which a strip clamp and a switch are provided between said reel and said metering roller, the passage of the end of said strip past said switch actuating said clamp to grip said strip.

7. A film feed drive comprising a feed roller having an axis of rotation, a photographic material wrapped around a substantial portion of said roller, a bracket swingable about said axis, a roller mounted on said bracket, said photo- 0 graphic material passing around said swingable ammmt' ERIC H. HEYER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 14,621 Wait Apr. 8, 1856 163,207 Kellberg May 11, 1875 1,891,225 Fear Dec. 20, 1932 1,968,166 Phythian July 31, 1934 2,029,854 Cannity Feb. 4, 1936 2,048,182 De Ybarrondo July 21, 1936 2,095,733 Coryell Oct. 12, 1937 2,153,552 Eitzen Apr. 11, 1939 2,291,627 Huck Aug. 4, 1942 2,338,422 Geyer Jan. 4, 1944 FOREIGN PATENTS Number Country Date 432,622 Germany May 29, 1925 410,859 Great Britain May 28, 1934 

